Invasive Species Management

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Need Noxious Weed Advice?

We are able to answer calls and questions. Our hours are Mon -Thur 6:30 am - 5 pm.  See our contact information on the right-hand side of this page.

What We Do

Orange hawkweed flowerhead.The Jefferson County Invasive Species Management program provides the public with information and offers solutions for managing invasive species and supports good stewardship of the land.  

We ensure the compliance with Colorado’s noxious weed, forest pest, and agricultural vertebrate pest regulations on private, county, and state lands.  We also provide technical assistance and support to county departments who are responsible for managing county owned lands.

The program coordinates with private, local, state, and federal agencies to achieve regional pest control.

Who We Are

Canada thistle flower.Our staff includes the Invasive Species Management Coordinator and limited summer help.

Weed of the Month

Each month we will feature a noxious weed to help landowners identify weeds they may encounter on their property.


May 2022


Cynoglossum officinale

Houndstongue is a member of the Boraginaceae family.  It is usually a biennial but occasionally acts as a short-lived perennial. It has hairy oblong leaves that form a rosette the first year.  In early-spring to mid-summer in its second year, it starts to bolt.  Between 1-8 stems grow from the crown.  They can reach a height of 40+ inches. The stems have reduced leaves.  Purple to magenta, five-lobed flowers are arranged loosely along the flower stem.  Each flower is less than 4/10 inch wide and when mature, forms a four-parted seed head called a nutlet.  Each nutlet contains one seed.  The nutlets are covered with barbs that can latch onto fur, gear, and equipment.  

The plants have a deep (to 40 inches), thick taproot but are easy to pull when very young.  If the plants have started to bud, they should be securely bagged and thrown in the trash. Houndstongue is also easily controlled with herbicide if treated pre-flower.

Most (~75%) seeds fall within a few inches of the mother plant.  Longer dispersal distances are via animals.

Known since 1830 in the US and 1897 in Colorado, Houndstongue is originally from Eurasia.  It is thought to have arrived in North America in contaminated cereal seed.  It is not strongly competitive but takes advantage of disturbance.

Houndstongue contains pyrrolizidine alkaloids and is poisonous to livestock.  These alkaloids may be found in higher levels at the rosette stage.  Animals tend to avoid live plants but when it is found in dried hay livestock will consume enough to be affected.


Weeds in Natural Areas

Utah State University

National Invasive Species Information Center


Root - John M. Randall, The Nature Conservancy,

Shoe - K. George Beck and James Sebastian, Colorado State University,

Flower - Joseph M. DiTomaso, University of California - Davis,

Native Grass Profiles

5394336-WEB-Bruce Bosley
1214062-WEB-Dave Powell

Western Wheatgrass

(Pascoplyrum smithii)      

Photos courtesy of

Western wheatgrass is a long-lived perennial grass that likes sunny, dry, sandy sites.  Its elevation range is between 3000 and 9500 feet. 

This cool-season grass grows erect to 30 inches tall and has rhizomes that form sod.  The narrow (about ¼ inch wide) leaf blades are blue-gray to green and are stiff with a mid-rib.

This grass flowers in June-August.  The flowers are arranged in 4- to 6-inch-long heads.

The ligule is fibrous and reduced.  The auricles are purplish and clasp the stem.

The best time to plant is mid-March through mid-April.

Western wheatgrass is used as forage for livestock and wildlife.  Because of its root structure it is used in revegetation projects and as a soil stabilization species.

Lady Bird Johnson Wildflower Center

NRCS  - Plant Profile (pdf)

SEINET - Plant Description

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A Landowner's Guide - Developing a Noxious Weed Management Plan

We developed this guide to assist landowners.  The information provides steps to develop a management plan for properties that have noxious weeds.

Download your copy

yellow_flag_iris Weed Spotter

The Weed Spotter program is a citizen science based effort to detect 6 high priority species on Jeffco Open Space parks.  Learn more at our Citizen Science page.